Manually set locking device



March 30, 1954 R. L. STRATTON MANUALLY SET LOCKING DEVICE 4 Shee'ts-Sheet l INVEN TOR. Kaag-,e r Snenrra'v E 5.

BY muy 9L VM@ A TTOR NE YS March 30, 1954 n. L. sTRATToN 2,673,946 MANUALLY sET LOCKING DEVICE Filed Nov. l0, 1951 4 Sheets-Sheet 2 IN VEN TOR. weer l. .S'rMn-av MEVMW A TTORNE YS March 30, 1954 TRATToN 2,673,946

MANUALLY SET LOCKING DEVICE March 30, 1954 R' L, STRATTQN 2,673,946 MANULLY SET` LOCKING DEVICE Filed Nov, 10, 1951 4 Sheets-Sheet 4 JN V EN TOR.

Patented Mar. 30, 1954 2,673,946 MANUALLY SET LOCKING DEVICE Robert L. Stratton, Folcroft, Pa.,

I-T-E Circuit assignor to Breaker Company, Philadelphia,

Pa., a. corporation of Pennsylvania Application November 10, 1951, Serial No. 255,860 Claims. (Cl. 317-55) My present invention relates to circuit breaker locking devices and more particularly it relates to manually operated locking devices that lock circuit breakers in the open position.

Their necessity arises from the fact that after 5 a fault has occurred in the circuit protected by the circuit breaker and the circuit breaker has opened the fault current, the circuit breaker could accidentally be closed, producingdamage to the electrical equipment connected to the circuit and in case the fault is being repaired, considerable harm to the repair crew.

To avoid any possible harm to operators and equipment, it is not only necessary to maintain open the circuit of the closing relay of the circuit breaker but also to lock the circuit breaker closing solenoid with the circuit breaker contacts in the open position'and the door or enclosure in the closed position. This ensures that even if the closing relay should accidentally be energized, the solenoid will not be able to move and thus close the circuit breaker contacts so as to energize the fault current.

To minimize the possibility that operators can manually close the circuit breaker of a fault line, a. the door giving access to the circuit breaker manual operating mechanism should also remain closed, or still better, locked in the closed position by a number of padlocks.

To be really effective a protective locking device for circuit breakers should incorporate all of these above features; it should also be easy to operate manually from the outside and above all its operation should not present any danger to the operator.

My present invention contemplates a manually operated cylindrical shaft carrying a cam and a lever. The cam operates a spring biased pin which after the opening stroke of the circuit breaker may be used to engage a slot machined in a shaft which is a part of the circuit breaker closing mechanism, thus locking the solenoid in the open position.

As the cam operates the pin to lock open the closing solenoid, the lever strikes a set of normally closed switch contacts in the circuit of the circuit breaker closing relay, thus opening the circuit of the circuit breaker closing relay. Once the shaft has rotated the amount necessary to perform the above-described operation, the handle of the operating shaft can be pivoted to engage a slot in the frame4 of the circuit breaker, thus locking the shaft in itsiinal position. y

Padlocks placed in anA appropriate slot of the operating shaft handle serve not only to entem which may sure that the shaft and the handle remain in that final position but also that the door or cover of the circuit breaker remains closed.

Furthermore, the provision that a plurality of padlocks, for example three, be used to lock the circuit breaker open ensures that all Workers having the necessary padlock keys must be present at the same time in order to unlock the circuit breaker. This makes impossible the accidental unlocking of the circuit breaker by one of the workers while the others are repairing the fault that caused the circuit breaker to open.

Accordingly, an object of my invention is to provide safety facilities in the operation and maintenance of the circuit breaker and its associated electrical system whereby a man or men working on said system at a point remote from the circuit breaker may be assured that the circuit breaker cannot be closed either manually or electrically. This is accomplished by the use of padlocks issued to each man working on the sysbe energized by the closing of the circuit breaker.

Another object of my present invention is. therefore, a locking device that will lock a circuit breaker in the open position, that will maintain the circuit breaker closing circuit electrically inoperative and will keep the door or cover of the circuit breaker mechanically closed.

A further object of my invention is the provision of means whereby this locking device for circuit breakers can be easily and safely operated from the outside, without opening the protective door or cover of the circuit breaker, thus avoiding any possible harm to the operators.

These and other objects of my invention will kbecome apparent in the following description when taken together with the drawings in which:

Figure l is a plan view of the locking device of my invention shown with the circuit breaker in the closed position.

Figure 2 is a front view of the locking device of my invention shown with the circuit breaker in the closed position.

Figure 3 is a .plan view of my invention shown in the open position.

Figure 4 is a front view of the locking device of my invention shown with the circuit breaker in the open position.

Figure 5 is a detail view switch used in my invention.

"Figure 6 is a perspective view of a circuit breaker incorporating my novel locking device.

of the locking device with the circuit breaker of the closing relay Figure 'l is a wiring diagram of the circuit breaker incorporating my invention.

Referring rst to Figure 6 showing a three-pole circuit breaker incorporating my present inven tion, circuit breaker 50 is mounted on a vertical support i and a horizontal base 5?. by any suitable means.

Circuit breaker is provided with three movable contacts 53 which engage in the circuit breaker closed. position their corresponding stationary contacts (not shown). An arc chute placed around the stationary contacts (not shown) serves to extinguish the arc 'that ywould exist between movable contacts .53 `and the stationary contacts (not shown) vat `the circuit breaker opening operation.

The three movable contacts 53 are tied together by means of a tie bar "50. Tie bar 55 Vmakes possible the simultaneous operation of the three movable contacts 53 so that if a fault should occur in the line connected topole 53a not only will movable contact '53a move to the open positionbut together with53a movable contacts 53h and 53e.

Movement of tie'bar 50 leads to vertical move ment oi cylindrical rod 58 Athrough the toggle mechanism generally referred to as "60. Cylindrical rod 5&3 is rigidly secured to a rectangular section block 32 carried on a shaft 63 rotatable in bearings eil of arms .65 of connecting link 63. Connecting link ,03 carries at its end 10 a shaft |0i so that `a rotation of link B8 in one direction produces a similar rotating movement oi shaft |0|.

A spring 12 secured at one end to post 15 and at its other end to link |53 serves to bias link 5t toward post 15 and, therefore, `to bias through rod 58 toggle 00 in the circuit breaker closed position.

When the circuit breaker 50 opens 'because of a fault, toggle Bil will break, moving lrod `53 upwardly and producing a clockwise rotation of link 08 under the bias `of spring 12.

Since, as previously mentioned, shaft |0| is rigidly secured tolink B8, shaft |'0| willalso rotate in a clockwise direction if link rotates in a clockwise direction.

t is thus seen that when circuit breaker 50 is tripped open, shaft |0| rotates in a clockwise direction for a certain `number of degrees. It is also quite evident 'that the trip open operation can also be performed manually through appropriate mechanisms (not shown).

When, on the other hand, the circuit breaker is to be closed, a crank (not shown) can be secured to shaft |0| to rotate shaft |0| in the counter-clockwise direction in this particular embodiment of my invention.

When shaft |0| rotates in the counterclockwise direction, link 'Se will also rotate in the same direction against the bias of spring 12, pulling down rod ce, rie-establishing toggle 00 and, therefore, moving the movable contacts 53 in current carrying engagement with the stationary contacts (not shown).

In order to make possible such a rotation of shaft i 0 it is necessary that shaft 0 beprovided with and be rotatable into a stationary bea-ring Bearing 1l is secured .to angle post .15 by means of nuts and bolt means 16.

Referring now to Figures 1 `and 2 showing the locking device of my invention in a detail view and tbe open position, circular shaft |3|, as previously mentioned, forms a part of the closing mechanism of the circuit breaker 50. Shaft icl rotates in one direction around its longitudinal axis .by during the closing stroke of the ciru cuit breaker and remains in Dthat position while iii) rder pin |04 -to receive shoulder pin the circuit breaker remains in the closed position.

When, on the other hand, the circuit breaker is tripped open, the shaft |0| rotates in the opposite direction by 90 to take the position shown in Figures 3 and 4.

A disc |02 of some thickness is mechanically fastened to shaft |0| so that it rotates together with shaft |0|. Through thisdisc |02 a slot |53 is machined (Figures 2 ,and 4). Disc |02 is so iastened on shaft |0| that slot |03 is so located as to cooperate properly with respect to the other parts of the locking device. More precisely, slot `|03 is so located that when the circuit breaker is tripped, slot ,|03 `moves exactly opposite shoul- Shoulder l,pin |-04 has two aligned cylindrical extensions |05 and |00. Extension |05 extends to the left (see Figures l, 2, 3 and 4) of shoulder |01 of pin |04 and extension |06 extends to the right of shoulder |01 of pin |04.

,Shoulder pin ,|04 is partly housed in structure |08 having a removable side 4plate |09 secured to structure II0?. by means of screws 0 engaging appropriate threaded bores ||i in opposite side plate ||2 of structure |08. Side plate |00 has an opening ||3 aligned with another opening in 4side plate ||2.

Openings 3 and I4 are large enough to allow extensions |05 and |06, respectively, of pin |04 to move freely through them. Shoulder pin |04 is biased away from engagement with slot |03 of disc |02 or toward the position where shoulder |01 of pin |04 rests against the side plate ||2 by means of compression spring ||5 located between side plate 109 and shoulder of pin |04 as shown in this preferred embodiment or by any other `appropriate biasing means.

Structure |08 is carried through bolts IIB and nuts |'1 by an angle ||18 `rigidly connected to the supporting angle 41li of the circuit breaker 50 by means of bolts, nut and washer means 15.

On 4the same angle 1| IB is lalso mounted by means of bolts |23 and lnuts 4|24 a normally closed switch |25, hereinafter `described in connection with Figure `5, whose contacts (see Figure 7) are connected in series with the closing switch |26 and pick-up coil |21 of the closing relay |28 ci the circuit `breaker 50.

In the circuit breaker open position as shown in Figures 3 and 4, extension |00 bears against a cam |29. Cam |29 is eccentric for this preferred embodiment, but otherwise of any suitable shape, and is secured by key |30 to an operating shaft |3| axially rotatable in bearing |32. Bearing |32 cylindrical shape has a closed end slot |33 and is attached to the door or cover |34 by a set of screws 4|35 engaging appropriate threaded bores in bearing |32.

To the sameshaft |3| are fastened a lever |30 and a handle |31 by means of keys |33 and |33, respectively. The handle |31 has a latch |40 `loosely pivoted around pivot point |4|. Latch |40 is equipped with a slot |42 which can accommodate a number of padlocks, for example three (not shown). The latch extension |43 of latch |40 can mesh with the closed end slot |33 in bearing l|32 when the handle |31 is turned 90 in clockwise motion `from the npositions shown in Figures 1 and 2. Operating shaft |3| in this particular embodiment is enclosed in a cylindrical sleeve |44.

vWhen the circuit breaker is tripped open, shaft |0| as previously shown rotates clockwise `90" to take `the `position shown in Figures 3 and 4. Therefore, disc |02 Aalso rotates by 90 moving slot |03 exactly opposite extension |05 of pin |04 ready to receive extension |05.

The operator now rotates the handle |31 by 90 clockwise, thus rotating also operating shaft |3| Iby 90 clockwise around its longitudinal axis.

The keyed cam |29 and lever |36 rotate together with shaft |3|, thus performing the following operations:

Cam |29 bearing against extension |06 of shoulder pin |04 pushes extension |05 of shoulder pin |04 against the bias of spring ||5 into engagement with slot |03 of disc |02 of the closing mechanism of the circuit breaker 50, thus mechanically blocking any rotation of shaft |0| of the closing mechanism.

Lever |36 pushes rod |45 which controls the normally closed switch |25. Switch |25, shown in detail in Figure', as previously mentioned is connected in series with the closing relay (see Figure 7). More specifically, switch |25 is provided with two stationary contacts |50 and |5| both secured to housing |58 of switch |25 in any suitable manner.

Contact |5| is connected to closing relay |28 while contact |50 is connected to control switch |26. Contacts |50 and |5| are normally bridged by a shorting bar |52 carrying two button contacts |53 and |54 in alignment with stationary contacts |50 and |5|.

Shorting bar |52 is rigidly secured and movable with the operating rod which extends in one direction through plate |51 of switch housing 58 and at Whose end there is a larger diameter portion |60. The other end |6| of rod |45 extends beyond shorting bar |52 and on it is placed a compression spring |63 which biases shorting bar |52 and, therefore, movable contacts |53 and |54 against stationary contacts and |5l, respectively.

When lever |36 strikes larger diameter seci tion of rod |45, rod |45 will be pushed against the bias of spring |63 to produce the opening operation between movable contacts |53 and |54 on one side and stationary contacts |50, |5| on the other side, thus interrupting the circuit between closing relay |28 (see Figure 7) and the control switch |26, thus rendering circuit .breaker 50 electrically inoperative.

Lever |36 rotated by means of handle |31 also serves to keep door |34 of switch 50 mechanically locked in the closed position since lever |36 after the above-described rotation of handle |31 will be located behind the stationary bracket H8. In other words, when lever |36 has been rotated so as to be behind bracket ||8, the door |34 cannot be swung open to afford undesirable accessibility to the circuit breaker closing means which, as previously described, could, for example, be a crank (not shown) engaging shaft |0| of circuit breaker 50. l

At the end of this rotation of handle |31, handle |31 is so positioned (Figures 3 and 4) that latch |40 can be pivoted and the latching extension |43 embedded in the slot |33 of bearing |32.

A number of padlocks, for example three, (not shown) may be set into the slot |42 of latch |40 to lock the circuit breaker 50 mechanically open and the closing relay coil |28 electrically open.

The use of a relatively large number of padlocks, three in this example, all havin-g different keys is necessary in that it prevents accidental opening of the circuit breaker 50 whilefone of the fholders of one key of one padlock is Vvgorking on the circuit connected to circuit breakerg-SU, for example, if the circuit lbreaker 50 had ltripped open because of a fault and the operator had turned handle |31 to lock the circuit breaker in this open position.

Assuming that a number of people who are in charge of circuit breaker 50 are three, three padlocks having each a different key are now placed in slot |42 and one key is given to each man.

It is now evident that if one of these three men is repairing a fault, no one else can accidentally close the circuit breaker in that access to the manual closing means will be prevented 'by the existence of these padlocks and even if one of n* the holders of such keys does open one of these padlocks, since the other padlocks are still in slot |42, it is obvious that he will not be able to rotate handle |31 to open door |34 of circuit breaker 50 to close the circuit breaker.

In the foregoing I have described my invention solely in connection with specific illustrative embodiments thereof. Since many variations and modifications of my invention will now be obvious to those skilled in the art, I prefer to be u bound not by the specific disclosures herein contained but only by the appended claims.

I claim:

1. In a circuit breaker having operating means comprising a normally closed switch and a clos ing relay coil, said switch for interrupting the circuit of said closing relay coil; a rotatable bar, said bar being axially rotatable, a slotted disc, said disc being fastened to and being rotatable with said bar, said bar rotating in one direction during the opening stroke and in the opposite if direction during the closing stroke of said circuit breaker, a manually operated shaft, a bearing, said shaft rotating in said bearing, said shaft having a cam and a lever; said cam and said lever' rotating with said shaft; a pin; said nin being biased against said cam, said shaft rotating said cam; said cam driving said pin into engagement with said slot of said disc after the opening stroke of said bar, said shaft also rotating said lever, said lever operating said normally closed interrupting switch, said bearing having a recess; said shaft having a handle on the side opposite said cam and lever, said handle comprising a loosely pivoted latch, said latch being engageable with said recess of said bearing at the end of rotation of said shaft; means locking said handle and shaft; said circuit breaker including a door; said door being locked in the closed position by said locking means.

2. In a circuit breaker having operating means comprising a normally closed switch and a closing relay coil, said switch for interrupting the circuit of said closing relay coil; a rotatable bar, said bar being axially rotatable, a slotted disc, said disc being fastened to and being rotatable in said bar, said bar rotating in one direction during the opening stroke of said circuit breaker. a manually operated shaft, a bearing, said shaft rotating in said bearing, said shaft having a cam and a lever; said cam and said lever rotating with said shaft; a pin;said pin being biased against said cam, said shaft rotating said cam; said cam driving said pin into engagement with said slot of said disc after the opening stroke of said bar, said shaft also rotating said lever, said lever operating said interrupting switch; said bearing having a recess;- said shaft having a handle on the side opposite said cam and lever, said handle comprising a loosely pivoted latch, said latch being engageable with said recess of said bearing at the end of rotation oi said shaft; means 'locking said handle `and shaft.

3.1m a circuit breaker lcomprising a pair of cooperable contacts, linkage mechanism, a closing relay coil., la normally closed switch, and a s ring biased pin; said cooperable contacts having an engaged and disengaged position, said age mechanism having a iirst and second po ion corresponding to said engaged and 4disn i c contacts; said normally closed switch posiM tioned in series with said closing relay coil, said `mechanism comprising a vrotatable bar and a slotted disc, Vsaid rotatable bar being axially rotatable and having said slotted disc .fastened thereto for rotation therewith, said rotatable bar rotated in a first direction during the movement oi said circuit breaker from contact engaged position to contact disengaged position, manually operable means comprising an operated shaft, a and a lever; said cam and said lever attached to operated shaft and rotatable therewith, spring biased pin biased against said cam, said operated shaft when Vmanually rotated from a 'first to a secon-d position causing said cam to drive said pin into engagement with said slot of disc when said. circuit breaker and said associated linkage mechanism are in contact diss engaged position, said operated shaft when manually rotated from said nrst to said second. position rotating said lever into engagement with id normally closed switch to thereby interrupt circuit to said closing coil,

i. In a circuit breaker comprising a pair of cooperable contacts, linkage mechanism, a closing relay coil, a normally closed switch, and a spring biased pii said cooperable contacts having an engaged and Vdisengaged position, said lineage mechanism having a first and second position corresponding to said engaged and disengaged positions, respectively, of `said oooperable contacts; said normally closed switch positioned in series with said closing relay coil, said linkage mechanism comprising a rotatable bar and a slotted disc, said rotatable bar being axially rotatable and having said slotted disc fastened thereto for rotation therewith, said rotatable bar rotated in iirst direction during the movement of said cir cuit breaker from contact engaged position to contact disengaged position, manually operable means comprising an operated shaft, a cam and lever; said cam and said lever attached to said operated shaft and rotatable therewith, said spring biased pm biased against said cam, said ged positions, respectively, ci `said cooperaoperated shaft when manually rotated from a iirst to .a second position causing said cam to drive said pin into engagement with said slot of said disc when 'saidcircuit breaker and said Vassociated linkage mechanism lare in contact disengaged position, said operatedshaft when manually rotated from said first to said second position rotating 'said lever into engagement with said normally closed switch to thereby interrupt the circuit to said `closing coil, said bar having a recess, said operatedishaft'having a handle on an end op-posite said cam and lever, said handle comprising a loosely pivoted latch, said latch being engageable with said recess of said bar when said shaft is rotated to said second position, said latch being locked in said engageable vposition to thereby lock said handle to said operated shaft.

`5. In afcircu'it breaker forprotecting an electric unit, a pair of cooperable contacts having a contact engaged `and a contact disengaged position, manually operable handle, a linkage 4extending from said handle to said contacts and having a contact engaged position and a contact disengaged position; said handle having a contact engagecl anda contact disengaged position, means including said handle land electromagnetic means responsive to a Lfault current in said electric unit for eiecting operation of said contact to disengaged position, said linkage effecting engagement of said cooperable contacts, a lock mechahaving one part `controlled by the operation o said contacts to disengaged position and a second part operable by 'said handle when said handle is operated to its second position, said parts interlocking -to lock said contacts and linkage in contact disengaged position and a lock mechanism for locking said 'handle in its `second position; electromagnetic mechanism; a circuit for energizing said electromagnetic `mechanism for operating said contacts to engaged position and contacts in said circuit locked open under control of said handle in its second position for rendering said electromagnetic mechanism nonenergizable to operate said contacts into engagement.

ROBERT L. STRATTON.

References Cited in the Tile of `this `patent UNITED STATES PATENTS 

